This invention relates to electrostatographic reproduction machines, and more particularly to electrostatographic reproduction machine including a simple low cost 1-N and N-1 cut output sheet receiving and stacking apparatus.
Generally, the process of electrostatographic reproduction includes charging a photoconductive member to a substantially uniform potential so as to sensitize the surface thereof. A charged portion of the photoconductive surface is exposed at an exposure station to a light image of an original document to be reproduced. Typically, an original document to be reproduced is placed in registration, either manually or by means of an automatic document handler (ADH), on a platen for such exposure. A set of 1-N such original documents can thus be fed seriatim by an ADH for such registration and platen exposure.
Exposing an image of an original document as such at the exposure station, records an electrostatic latent image of the original image onto the photoconductive member. The recorded latent image is subsequently developed using a development apparatus by bringing a charged dry or liquid developer material into contact with the latent image. Two component and single component developer materials are commonly used. A typical two-component dry developer material has magnetic carrier granules with fusible toner particles adhering triobelectrically thereto. A single component dry developer material typically comprising toner particles only can also be used. The toner image formed by such development is subsequently transferred at a transfer station onto a copy sheet fed to such transfer station, and on which the toner particles image is then heated and permanently fused so as to form a "hardcopy" or finished copy of the original image. The finished copy of each original document is then fed to an output tray for subsequent removal and use by an operator.
One of the challenges encountered in the handling of finished copies, particularly a set of 1-N finished copies made from a set of 1-N original documents handled by an ADH, is how to logically receive and stack the output set. There are of course situations in which it is desirable to stack such an output set 1-N, and other situations in which the desired stacking sequence is N-1.
Conventionally, many attempts have been made to meet this challenge. For example, U.S. Pat. No. 4,220,323 issued Sep. 2, 1980, discloses a sheet receiving and stacking apparatus having a guide member and two sheet supporting surfaces for receiving and stacking cut sheets in a first orientation or in an inverted orientation. The guide member has a first position for directing sheets in the first orientation onto a first supporting surface, and a second position where it forms the second surface for receiving and stacking the sheets in the inverted orientation.
U.S. Pat. No. 4,384,782 issued May 24, 1983, discloses a reproduction machine including a 1-N order document copying sheet handling apparatus. The sheet handling apparatus is adapted for selectively feeding document sheets from one end of a top of a stack of such sheets, in a forward direction for copying, and restacking the copied sheets at the bottom of the opposite end of the same stack in the same order. The sheet handling apparatus includes an intermittent lifting device that combines with a vacuum belt for lifting the opposite end, a vacuum belt transport, and an air flotation device.
There is therefore still a need in an electrostatographic reproduction machine for a simple and less costly apparatus for receiving and stacking cut output sheets in 1-N and N-1 sequence.